1. Field of the Invention
The present invention relates to a chord detecting apparatus and method capable of automatically detecting a chord based on the inputted note information, and more particularly to such a chord detecting apparatus and method in which the chord detecting modes are automatically selected according to the depressed key patterns. The invention is applicable in an electronic musical instrument, an automatic accompaniment apparatus connected to an electronic musical instrument, an automatic performance apparatus which automatically performs music based on performance data previously stored in the apparatus or externally supplied from an outside apparatus.
2. Description of the Prior Art
Electronic musical instruments, automatic accompaniment apparatuses and automatic performance apparatuses are conventionally equipped with a chord detecting apparatus which automatically detects chords based on note data inputted thereto representing names in a musical scale, and are capable of automatically generating chord tones, arpeggio tones, bass tones and various other automatic accompaniment tones. Keyboard electronic musical instruments typically employ two types of chord designating methods usually referred to as a fingered chord mode and a single finger mode, respectively. The fingered chord mode is to designate a chord by simultaneously depressing a plurality of keys corresponding to all or some of the chord constituent notes of an intended chord, and is suited for advanced players. The single finger mode is to designate a chord by simultaneously depressing a single key corresponding to the root note of an intended chord plus zero or one or more additional keys below the root note key to determine the type of the intended chord such as a major, minor and seventh chords, and is suited for beginner players.
Therefore, the conventional chord detecting apparatus is typically constructed such that the designated chord is detected from the combination of all or some of the chord constituent notes represented by the inputted note information (data) for the fingered chord mode detection on the one hand, and that the designated chord is detected from the combination of the root note and a few (including zero, in this instance) additional note(s) under a predetermined rule represented by the inputted note information (data) for the single finger mode detection on the other hand. There have been prevailing two types of methods for determining (or selecting) a mode for use from among those chord detecting modes. One is to determine the mode by a manual selector switch for selecting either of the fingered chord mode and the single finger mode. The other is to determine the mode automatically based on the depressed key pattern by primarily detecting the chord according to the fingered chord detecting rule and secondarily detecting, only in case the primary detection has failed, the chord according to the single finger chord detecting rule.
With the apparatus employing the above first method for determining the chord detecting mode, however, it is troublesome to manually change over the mode selector switch amidst playing music, and moreover there may be an unintended chance where a chord which is not intended by the player is detected if the player should fail to properly change over the mode selector switch. On the other hand, the apparatus employing the above second method for determining the chord detecting mode have another problem especially with the apparatus utilizing advanced chord detecting algorithm having rules for many complicated chord designations. Namely, if the player depresses the keys according to the single finger detection rule (according to his/her intention) but the depressed keys happen to be the same as one of the fingered chord determining patterns, the apparatus automatically detects the chord according to the fingered chord rule contrary to the player's intention.